ML20214K440
| ML20214K440 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 11/12/1986 |
| From: | Rice P GEORGIA POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-86-375-000 GN-1172, PT21-86-375, PT21-86-375-000, NUDOCS 8612020305 | |
| Download: ML20214K440 (3) | |
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h 3-Georgts Power Cornpany Po:st Offee Box 282 i
i Waynesborn Georgia 30830 Tewone 404 554-996t, Ext. m 3413 404 724 8114. Ext. W4 C(i h'0'.! 18 All : 9n GeorgiaPbwer P. D. Rice QP,'y ee saeem wtw swem November 12, 1986 United States Nuclear Regulatory Commission Region II File: X78G03-M126
. Suite 2900 Log:
GN-1172 101-Marietta Street, Northwest Atlanta Georgia 30323
Reference:
Vogtle Electric Generating Plant-Units 1 and 2; 50-424, 50-425; Conax Electrical Penetration-Assemblies; Letter GN-1091, dated September 29, 1986 Attention: Mr. J. Nelson Grace In previous correspondence, Georgia Power Company described a potentially reportable condition concerning the discovery of some leaking containment electrical penetration assemblies.. Georgia Power Company has completed its evaluation and determined that a reportable condition as defined by the reporting criteria of Part 10 CFR 50.55(e) and Pa;'t 10 CFR 21 does exist.
Based upon NRC guidance in NUREG-0302, Revision 1,
and.other NRC correspondence, Georgia Power Company is reporting this condition pursuant to the reporting requirements of Part 10 CFR 50.55(e). A summary of our evaluation is attached.
This response contains no proprietary information and may be placed in the USNRC Public Document Room.
Yours truly, fh P. D. Rice l
REF/PDR/tdm Attachments l
xc:
U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555 L
H. G. Baker D. R. Altman L. T. Gucwa i
J. P. O'Reilly P. R. Bemis C. W. Hayes G. F. Head J. A. Bailey G. A. McCarley R. E. Conway
- 0. Batum R. W. McManus R. H. Pinson G. Bockhold Sr. Resident (NRC)
C. W. Whitney C. E. Belflower C. C. Garrett (OPC)
B. H. Guthrie J. F. D'Amico J. E. Joiner (TSLA) l D. E. Dutton W. D. Drinkard D. Feig (GANE)
R. A. Thomas E. D. Groover NORMS I
l 8612O20305 861112 8 d L
PDR ADOCK 05000424 l
S PDRJ l
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EVALUATION OF A POTENTIALLY REPORTABLE CONDITION CONAX ELECTRICAL PENETRATION ASSEMBLIES Initial Report: On September 5, 1986, Mr. R. E. Folker, Vogtle Project Quality Assurance
- Engineer, informed Mr. E. F. Christnot of the USNRC-Region II of a pot.entially reportable condition concerning leakage through a drilled hole in the side of the penetration header plate on some Conax electrical penetration assemblies.
This condition was initially identified in 0perational Deficiency Report ODR-T-1-86-2941.
In subsequent correspondence to the NRC, Georgia Power Company indicated that a final report on this condition would be submitted by November 14, 1986.
Background Information: Electrical penetration assemblies provide passage of electric conductor through a single aperture in the nuclear containment structure, while providing a pressure barrier between the inside and the outside of the containment structure.
Each electrical penetration assembly is required to withstand the pressure, temperature, and environmental conditions resulting from a design basis accident (DBA) without exceeding the electrical penetration design leakage rate.
According to IEEE 317, each penetration assembly shall have a total gas-leak rate not greater than 1 x 10 2 3
std cm /second of dry nitrogen.
During Unit 1 containment building structural integrity testing it was discovered that the following electrical penetration assemblies were leaking air from inside the containment intc the control building:
1-1818-H3-P05 1-1818-H3-P06 1-1818-H3-P07 1-1818-H3-P51 1-1818-H3-P53 1-1818-H3-P54 These electrical penetration assemblies were procured from Conax Corporation under specification X3AB03.
Each of the above penetration assemblies has six rows of feed-throughs for a total of 33 feed-throughs.
In order to interconnect each feed-through, a hole for each row is drilled in the side of the header plate during manufacturing.
A hole is also drilled in the bottom of the header plate to interconnect the rows.
After drilling, all of the holes are plugged at the periphery of the header plate.
However, inspection revealed that each of the identified penetration assemblies was leaking through the bottom-most of the six holes that were drilled on the side of the header plate during manufacturing.
These holes had not been properly plugged by the manufacturer.
Engineering Evaluation: These penetration assemblies are designed to pass electrical conductors through the containment wall while maintaining the containment leak rate integrity during normal LOCA and post-LOCA conditions.
This deficiency, had it remained uncorrected, represents
e an unanalyzed condition that could result in LOCA and post-LOCA containment leakage in excess of that assumed in the plant safety analysis and could possibly have resulted in offsite radiation doses in excess of 10CFR 100 guidelines.
Quality Assurance Program Breakdown Evaluation: It has been determined
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that this condition resulted from a lack of consideration of containment pressure in the Conax testing program and not a significant QA program breakdown in Conax's quality assurance program.
This determination was based on a review of the Final Engineering Evaluation Report, Quality Surveillance Reports including
, hipping releases and Audit Reports
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of Conax, and discussions with Vogtle Project engineering personnel.
In addition, the most recent QA a'idit of Conax (conducted by Bechtel) determined that their QA Program was acceptable.
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Conclusion:==
Based on the above evaluation, Georgia Power Company has concluded that this condition is reportable per the reporting criteria of Parts 10CFR21 and 10CFR50.55(e).
Based upon guidance in NUREG-0302, Revision 1 and other NRC correspondence, Georgia Power Company is reporting this condition pursuant to the reporting requirements of Part 10CFR50.55(e).
Corrective Action: Upon notification of the problem, Conax manufactured a plug for each penetration.
A Field Change Request (EFCR-B-686-N) was generated with a repair procedure prepared by Conax's field service engineer, to weld the plug into the hole in the header plate.
This repair provided a satisfactory environmental seal for each of the holes.
The same model penetrations in Unit 2 were checked and all were found to have plugs at the periphery of the header plate and were me.intaining the dry nitrogen pressure.
Therefore, it is concluded that the corresponding Unit 2 penetrations do not have this deficiency.
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